The instant invention relates to a cartridge comprising a cartridge case having a primer cap at its bottom, and a metal flash tube extending into the cartridge case immediately after the primer cap. The metal flash tube extends about one-third of the length of the combustion chamber in the cartridge case and is surrounded by the propellant charge.
Conventional cartridges do not have a flash tube extending into the cartridge case. In conventional cartridges, a primer cap at the bottom of the cartridge case initially ignites the propellant charge located at the bottom of the cartridge case. The propellant charge then detonates from the bottom to the top where the projectile is located. This has the disadvantage that the combustion gases which first develop compress the layers of propellant charge located at the top of the cartridge case, thereby rendering it more difficult for these to detonate. At times, the undetonated compacted propellant mass located at the top of the cartridge case is expelled together with the projectile, the full effectiveness of the propellant charge therefore not being utilized.
In order to remedy this disadvantage, a flash or ignition tube extending into the cartridge and filled with a detonating agent is sometimes provided. See, e.g., U.S. Pat. No. 4,572,078 (Bell) which discloses a metal flash tube surrounded by propellant charge in the cartridge case. The periphery of the metal flash tube disclosed therein has perforations so that the detonating agent can ignite the propellant charge. However, this patent recognizes that a limitation of this arrangement is that there is low uniformity of propellant bed permeation by the flash produced in the flash tube. Furthermore, because of the presence of the perforations, even in this arrangement the propellant charge is ignited from the bottom of the cartridge case upwards and not suddenly all at once. While the arrangement shown in FIG. 1 of U.S. Pat. No. 4,572,078 leads to an improvement in the situation, this arrangement is not a totally satisfactory solution.
The same U.S. Pat. No. 4,572,078 also teaches that the flash tube may be omitted and the inside walls of the cartridge case can be lined with a thin layer of the detonating agent extending up from the primer cap. However, this arrangement leads not only to difficulties in manufacture but also fails to produce a truly sudden detonation of the entire propellant charge.
It is also known from DE-AS 1 296 998 that instead of a metal flash tube, a pipe-shaped sleeve made from a combustible material and containing a powder-like detonating agent can be provided, whereby a coaxial pyrophoric element is contained within the cartridge case. However, since the pipe-shaped cartridge sleeve disclosed therein only extends about one-third of the length of the cartridge case, this arrangement also produces a progressive ignition of the propelling charge, starting from the bottom of the case and up to the projectile.
It is therefore the object of the instant invention to eliminate these disadvantages and to provide a cartridge in which the sudden ignition or detonation of the propellant charge over the greatest possible surface is ensured through comparatively simple means.